Mitochondrial acetyl-CoA acetyltransferase 1 promotes the Warburg effect

线粒体乙酰辅酶A乙酰转移酶1促进Warburg效应

• 批准号: 9212121
• 负责人: Jing Chen
• 金额: $ 32.51万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-03-01 至 2019-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9212121
• 关键词: Acetyl Coenzyme A; Acetyl-CoA C-Acetyltransferase; Acetylation; Acetyltransferase; Anabolism; Attenuated; Binding; Cell Proliferation; Cells; Citric Acid Cycle; Coenzyme A; Deacetylase; Enzymes; FGFR1 gene; Gene Expression; Genome; Glucose; Glycolysis; Libraries; Lipids; Lysine; Malignant Neoplasms; Malignant neoplasm of lung; Mediating; Metabolic; Mitochondria; Molecular; Normal Cell; Normal tissue morphology; Nucleotides; Oncogenic; Oxidative Phosphorylation; PDH kinase; Phenotype; Phosphorylation; Protein Dephosphorylation; Protein Tyrosine Kinase; Proteomics; Pyruvate; Pyruvate Dehydrogenase (Lipoamide)-Phosphatase; Pyruvate Dehydrogenase Complex; Recruitment Activity; Regulation; Reporting; Resistance; Serine; Signal Transduction; Site; Tyrosine Phosphorylation; Warburg Effect; aerobic glycolysis; c-myc Genes; cancer cell; in vivo; knock-down; leukemia; macromolecule; mimetics; mutant; novel; public health relevance; pyruvate dehydrogenase; small hairpin RNA; tumor; tumor growth; tumor metabolism

DESCRIPTION (provided by applicant): The metabolic switch from oxidative phosphorylation to aerobic glycolysis in cancer/leukemia cell has been suggested to be due to, in part, attenuated mitochondrial function, which is suggested to be achieved through inhibition of pyruvate dehydrogenase complex (PDC). Pyruvate dehydrogenase A (PDHA) is the first and most important enzyme component of PDC, which converts pyruvate to acetyl-CoA that subsequently enters into the Krebs cycle. PDHA activity is negatively regulated by phosphorylation at several serine sites. Phosphorylation of PDHA by PDH kinase 1 (PDHK1) results in the inactivation of PDC, while dephosphorylation by PDH phosphatase 1 (PDP1) restores PDC activity. Although PDHK1 has been suggested to be upregulated by Myc and HIF-1a, how oncogenic signals inhibit PDC to regulate cancer cell metabolism still remains largely unknown. Interestingly, our proteomics studies revealed that in cancer cells, PDP1 and PDHA are inhibited by acetylation at K202 and K321, respectively. Moreover, we identified mitochondrial acetyl-CoA acetyltransferase 1 (ACAT1) as the upstream enzyme that acetylates and inhibits PDP1 and PDHA, and consequently PDC flux. Furthermore, we found that oncogenic FGFR1 phosphorylates and activates ACAT1. Stable knockdown of ACAT1 in cancer cells results in decreased glycolysis and increased OXPHOS, as well as reduced cancer cell proliferation and tumor growth. Thus, our hypothesis is that oncogenic TKs such as FGFR1 phosphorylate and activate mitochondrial ACAT1 to inhibit PDHA and PDP1 via lysine acetylation, which consequently attenuates PDC function to promote the Warburg effect and tumor growth. This represents a new concept that the transforming signals of oncogenic TKs could be mediated at least in part through regulation of lysine acetylation levels of key downstream effectors. Three Specific Aims are proposed: (1) To determine whether FGFR1-dependent tyrosine phosphorylation of ACAT1 is important for ACAT1 activation and promotion of cancer metabolism and tumor growth; (2) To elucidate the molecular mechanisms by which ACAT1 binds to, acetylates and inhibits PDP1 and/or PDHA; (3) To examine whether ACAT1-dependent lysine acetylation of PDHA and PDP1 in cancer cells is sufficient to promote the Warburg effect and tumor growth.

描述(申请人提供)：肿瘤/白血病细胞代谢从氧化磷酸化到有氧糖酵解的转变被认为部分是由于线粒体功能减弱，这被认为是通过抑制丙酮酸脱氢酶复合体(PDC)来实现的。丙酮酸脱氢酶A(PDHA)是PDC的第一个也是最重要的酶组分，它将丙酮酸转化为乙酰辅酶A，然后进入Krebs循环。PDHA活性受几个丝氨酸位点的磷酸化负调控。PDH激酶1(PDHK1)对PDHA的磷酸化导致PDC失活，而PDH磷酸酶1(PDP1)去磷酸化则恢复PDC的活性。虽然已发现PDHK1被Myc和HIF-1a上调，但致癌信号如何抑制PDC调节癌细胞代谢在很大程度上仍不清楚。有趣的是，我们的蛋白质组学研究表明，在癌细胞中，PDP1和PDHA分别在K202和K321处被乙酰化抑制。此外，我们还发现线粒体乙酰-辅酶A乙酰转移酶1(ACAT1)是上游酶，其作用是乙酰化和抑制PDP1和PDHA，从而抑制PDC通量。此外，我们还发现致癌的FGFR1磷酸化并激活ACAT1。在癌细胞中稳定地敲除ACAT1导致糖酵解减少和OXPHOS增加，以及减少癌细胞增殖和肿瘤生长。因此，我们的假设是，致癌的TKS如FGFR1磷酸化并激活线粒体ACAT1，通过赖氨酸乙酰化抑制PDHA和PDP1，从而减弱PDC功能，促进Warburg效应和肿瘤生长。这代表了一个新的概念，即致癌TKS的转化信号至少部分通过调节关键下游效应物的赖氨酸乙酰化水平来介导。我们提出了三个具体目标：(1)确定ACAT1依赖于FGFR1的酪氨酸磷酸化是否对ACAT1激活以及促进癌症代谢和肿瘤生长重要；(2)阐明ACAT1与PDP1和/或PDHA结合、乙酰化和抑制的分子机制；(3)检测癌细胞中依赖ACAT1的PDHA和PDP1的赖氨酸乙酰化是否足以促进Warburg效应和肿瘤生长。